DE102005000851A1 - Window wiper blade for a vehicle has a rubber wiper lip onto which polymer film or granulate is applied - Google Patents

Abstract

A vulcanized rubber wiper blade(2) has a wiping lip onto whose surfaces either a film(4,7) is bonded or a granular layer is applied. Films(4) are bonded onto the lip either with a separate adhesive(6) or by use of a self adhesive film(7). The film or granular material may be applied only onto the front part of both flanks of the wiper lip or over the whole area. Particle size of the granules is not >100microns. Post vulcanization of a granule covered lip using either a laser, a gas burner, salt bath or infra-red heating forms a chemical bond between granules and rubber. Independent claims are included for: a) processes for manufacturing the wiper blade in which a synthetic rubber wiper blade is vulcanized and either a film is applied onto the lip or a layer of granules is applied; b) a rubber door or window seal for vehicles whose rubber lip has an applied film or granulate layer.

Description

The The invention relates to a wiper blade for a windscreen wiper and a method for its preparation according to the preamble of the independent claims.

Usually Today, the wiper blade belonging to wiper blades or wiper blades, which for example, to remove drops of water on the windshield of motor vehicles and to the front of the windscreen. and movable windscreen wipers attached to a windscreen wiper system be, injection molded or extruded endless. This is a previously mixed and unvulcanized rubber starting material, eg. an unvulcanized synthetic rubber, molded and vulcanized. Because of economical reasons has in both processes the simultaneous production of Double profiles enforced. After completion of vulcanization is the surface the rubber wiper strip thus obtained usually aftertreated, to the frictional resistance of the disk to be wiped accordingly to reduce the requirements or the sliding of the To improve the wiper strip on the window to be wiped. Of the desirable coefficient of friction μ may at a temperature t of 23 ° ± 5 ° C and a relative humidity of 50 ± 3% do not exceed the value of 2.0. The mentioned surface post-treatment For example, in a hardening of the surface of the Wiper rubber strip by chlorination, bromination or in a coating the same, in order to achieve a surface layer on the wiper strip, which a fine lubricating powder, for example, powdered molybdenum disulfide contains. Although the chlorination minimizes the frictional resistance and that slipperiness improved, the achieved improvement for one proper running of the wiper is not enough. Applying a dry lubricant-containing surface layer is with the disadvantage connected, that the same after a short period of use of Wiper strip is scraped off, so it lacks the necessary stability.

The DE 197 41 225 A1 discloses a wiper blade comprising a body made of an elastomeric material and a surface coating layer disposed on a surface of the body and including a fluorine-containing resin containing reactive groups and a curing agent exhibiting reactivity with the reactive groups.

In the DE 101 25 045 A1 a wiper blade for a windshield wiper, in particular for a windshield wiper of a motor vehicle is proposed which has a squeegee with a squeegee lip. In order to achieve a low dry friction, the squeegee lip is partially made of polyethylene. The preparation of the wiper blade is done by vulcanizing a rubber material together with polyethylene.

task The present invention is therefore a simple and environmentally friendly Solution for the above The problems of the prior art mentioned above are available and a wiper blade with excellent wiping performance and to provide a long service life at the same time.

Advantages of invention

With The present invention provides a product improvement both in terms of increasing the wear resistance while maintaining the excellent wiping quality over the Lifespan of the wiper as well as by a friction coefficient reduction achieved to a value of μ <0.8. By a reduction in the total number of manufacturing steps as well as by the use only Inline-capable process steps a significant simplification of the overall process is achieved.

The inventive method for producing the wiper blade has over the prior art the Another advantage that in the surface treatment of the wiper blade rubber no free chlorine or bromine is formed, since no halogenation of the Wiping rubber is required.

Also It is advantageous that the durability and the coefficient of friction reduction significantly higher is as with coatings, as known from the prior art are. Furthermore, it is advantageous that no pollution by replacement (Abrasion) of the surface layer arises.

One Another advantage is that the direct and indirect costs the surface treatment can be greatly reduced, because of a halogenation of the surface of the wiper blade to be produced can be waived.

advantageous Further developments of the invention will become apparent from the mentioned in the dependent claims Activities.

embodiments

Core of the invention is the use of films or granules for surface coating of wiper blades. Suitable materials are included applied as part of the production process for producing the wiper blades. With this technology, improved product properties are easy to realize due to the existing variety of materials in films and granulates.

It It should be noted that the present invention is not limited to Blades of wiper blades for windscreen wipers is applicable, but in the same way also for door or window seals, especially for Doors and Window of motor vehicles can be used. Hereinafter For the sake of simplicity, however, it is only intended for use with wiper blades to be discribed.

preferred Material for Films and granules for coating wiper rubbers are High Molecular Weight Polyethylene or Ultra High Molecular Weight Polyethylene (HMW-PE, UHMW-PE), as this is particularly resistant to wear and a sufficient has water-repellent function. But there are other materials as well such as polyethylene (PE), fluorinated ethylene-propylene (FEP), polyphenylene ether (PPE), perfluoroalkoxy polymers (PFA), polycarbonate (PC), polyoxymethylene (POM), polyacrylate (PA), polyurethane (PUR), polytetrafluoroethylene (PTFE) or a laminate of different thin layers of these materials and granule mixtures usable. The grain size of the granules used is preferably below 100 microns. A use of larger grains can u. U. lead to a reduced wiping quality.

The preferred rubber material to be coated on the wiping rubbers is ethylene-propylene-diene monomer (EPDM), but also ethylene-propylene monomer (EPM), chloroprene rubber (CR), natural rubber (NR) and mixtures thereof are usable.

at the use of Reibmindernden films as coatings the surface the wiper blade of a squeegee becomes the foil in the middle mounted in the form of a double profile squeegee. The Application can be carried out by means of an adhesive, it can but also self-adhesive films are used.

As already mentioned, the simultaneous production of double profiles has prevailed in the previous methods for producing wiper blades, especially for economic reasons. Wiper blades with suitable profiles (or cross sections) are generally extruded continuously from vulcanizable polymer blends, vulcanized and then singulated. 1A shows such a double profile 5 , and 1B a single profile 1 after cutting the double profile 5 out 1A ,

According to one embodiment of the present invention, a film strip is now after vulcanization and a possible cleaning step 4 , for example made of PE or PA, on both sides of the surface of the wiper blade rubber 3 applied. This can, for example, by means of a suitable adhesive 6 , For example, a hot melt adhesive happen or it can be a self-adhesive film 7 be applied. In 4 the workflow is shown schematically. The extruded, vulcanized and cleaned double profiles 5 be by means of a conveyor belt 8th in the direction of the arrow 9 moved while using adhesive 6 applied films 4 at an adhesive dosing device 10 passed past, where the adhesive is applied to the surface of the wiper blade rubber. From a roll 11 on which the foil strips 4 are wound, the film is then fed to the double profile strand and with the help of pressure rollers 12 and corresponding counter-rolls 13 pressed with the strand. The provided with the film strand is then continued for gluing the second side and then cut to a predetermined length. In case of using self-adhesive film 7 can the adhesive metering device 10 accounted for and the role 11 contains the self-adhesive foil 7 , Due to economic advantages (only one operation), an application to the not yet cut double profiles offers 5 on (cf. 1A ), but also already cut individual profiles can, as in 2A shown to be pasted. The 2 B shows a single profile with finished glued foil strips 4 respectively. 7 , The film strips preferably have a thickness in the range of 15 to 300 microns.

This Procedure has the advantage that not in existing, known process steps must be intervened. Furthermore can the squeegee opposite cut to length Wiping rubbers during the application can be handled easily.

The adhesive film can be applied to already known rubber profiles, but it is possible due to the ease of handling, all conceivable profiles, so that this method is universally applicable. The 3A and 3B show the application of the adhesive film 4 . 7 on any profile 8th , The advantage of the profile shown here is that only one adhesive strip is needed instead of two as in conventional profiles.

In another embodiment of the present invention, the film can also be applied before the actual vulcanization step. By applying the wiper blade with heat, the film is thereby vulcanized or melted onto the rubber. This can be done in different ways and done way. One possibility is the application in the extruder head at the end of the nozzle. In this way, the film is transported by the flow of the extrudate. Due to the pressure inside the nozzle, the film adheres very well to the not yet vulcanized extrudate. This is important because the film has to adhere well to the rubber during vulcanization or melting, so that a constant adhesion after vulcanization is ensured. This solution is the most cost effective, as no further changes in the existing process are necessary. Further advantages of this solution are the stable bonding conditions immediately after the nozzle. However, care must be taken that the film is not damaged when inserted into the nozzle.

A another possibility consists in applying outside the nozzle with the help of rails, pinch rollers or the like. In case of still Unvulcanized rubber requires the two pressure systems to provide a setting for the exact variation of the height, over a predetermined thickness the length of the strand to be able to Unvulcanized rubber has lower stability. The not yet vulcanized rubber is between these Andruckstellen passed, wherein the film is applied. It is important that the geometry of the profile is not disturbed by the pressure mechanism.

In a further embodiment of the present invention, the film, as in the preceding Section described, applied to a semi-vulcanized rubber. Semivulcanized means that the rubber is after a certain Vulkanisierzeit from the salt bath or oven is taken and therefore only partially vulcanized. This has the advantage that the rubber not as fragile as an unvulcanized rubber. Becomes a salt bath used for vulcanization must be ensured that the surface is cleaned and dried to ensure good adhesion of the film guarantee. It is still recommended to apply the rubber before applying To heat foil to achieve constant bonding conditions, however, in this Case are no longer as good as when using a non-vulcanized Rubber. There is thus the danger in this embodiment not stable adhesion.

The Apply the film to the cut to length rubbers with Help of a template is also possible. This is the template heated, whereby the film vulcanized onto the rubber or melts. For this purpose, a large system is required, where a set of templates that transports rubbers.

At the Attach the film completely Vulcanized rubber must be applied to the film with the help of heat become. The adhesive force is no longer sufficient in this case, to adhere properly to the film. With the help of a pressure system is while the film vulcanized on the rubber or melted. A disturbance The geometry is excluded if a greater pressure force is used. The disadvantage can be in this case that for the pressing and Melt up additional Devices needed become.

As already mentioned, can the increase of the invention wear resistance while maintaining the excellent wiping quality over the Wiper life and friction coefficient reduction to one value from μ <0.6 also by the application of a granulate can be achieved on the squeegee. In this case, a certain amount of granules using conventional Processes applied to the rubber, for example. With the help of a metering wheel. By a toothed wheel, the granules are dosed and rotating to brush thrown on the rubber. Another possibility is the use the powder coating process. Here, the granules by means of a Nozzle and Compressed air applied to the rubber. Due to the good adhesive power of the rubber is an electrostatic charge of the rubber or granules is not necessary. It is also possible to apply by means of vortex sintering. It will the granules are applied in a whirling bath. It is important make sure that the powder or granules in the vortex tank not contaminated by foreign matter, causing sticking together of the granules may occur under formation of particles which can affect the wiping image. Finally, can the granules also by spraying be applied from a suspension to the rubber. By the Adhesive properties of pure rubber, the granules remain at the surface be liable.

At the Applying the granules, it is important to maintain a constant powder density to get over to the entire rubber length to obtain a stable friction. It may be necessary to the granules first in excess apply and then the surplus Controlled by blowing off with compressed air or with the help of a Remove the suction system again. The adhesive strength of the Rubbers the powder density, since only so much powder is absorbed as the adhesive strength of the rubber pretends. If necessary, a Primer can be used, which takes over the initial adhesive effect. Subsequently This primer can evaporate during vulcanization. This method is mainly used when using already cut profiles.

Alternatively, the entire rubber profile can be coated with the granules or just that Area in the area of the wiper lip. An advantage of coating the entire rubber profile is, for example, better handling during the cutting process.

To the application of the granules is then in a subsequent step the Granules by supplying heat, For example, by a salt bath, an oven, by means of an IR heater or Like. Vulcanized on the rubber. It will be partly melted.

It is possible, the granules immediately after the extrusion to continuous Apply rubber strands. The granules are preferably applied before vulcanization, so that during vulcanization also the granules vulcanized onto the rubber becomes. This is the least expensive Solution, there are no other changes necessary in the known process. Further advantages of this procedure are the stable bonding conditions immediately after the nozzle, as the Rubber is not dirty and the high temperature is favorable the adhesion during application of the granules affects. However, it is to take care that during the Applying no forces occur that can affect the geometry of the rubber since the rubber strand after vulcanization is very sensitive to deformation is. In this process variant, it is of particular advantage when the extruded rubber strand or the granules to be applied before the order, for example, by an electrical contact is electrostatically charged. This improves the adhesion of the Granules on the surface of the still unvulcanized rubber strand.

A subsequent vulcanization, for example, in a corresponding Tempered salt bath. This results in a bristle-like structured surface vulcanized rubber strand suitable for use as a squeegee is usually suitable, but still by a smoother example can be improved by a suitable heat treatment.

A another possibility consists in a vulcanization in air, for example by the action of hot air or heat radiation. This melt the applied granules and form without aftertreatment already a sufficiently smooth surface.

A another possibility is the application of granules after vulcanization and fusing with the rubber through an additional post-vulcanization step. In this process, both a semi and a fully vulcanized rubber be used. However, it is necessary to use the rubber in one additional Process step to clean, before old then when to vulcanization a salt bath is used. All salt residues must be removed, as these are on the one hand prevent the vulcanization and on the other hand, the adhesive properties influence negatively.

It may also be necessary, the rubber surface before applying easily to warm up to to obtain a stable, continuous adhesive power. At this embodiment it is advantageous that the rubber is already geometrically stable, that is to say that there are greater forces can act on the rubber, without deforming or even destroying it.

It is also possible the rubber profile runs vertically through the apparatus instead of horizontally to let, what the uniform discharge favors, because the influence of gravity for both sides of the coating is equal to. When applying a Postvulkanisierungsschrittes with Fully vulcanized rubber, the application process can also immediately be performed before the cutting process of the rubber. In this case are already cut to length Double profiles used. In this way, the application process decoupled from the extrusion process, with failures during application of the granules do not affect the extrusion process. It should be noted that In this case, the transport system process the rubber with very high friction got to.

Of the Post vulcanization step can be done in different ways carried out become. First Is it possible, the granules during application by means of a laser (eg Coaxial laser) directly vulcanize. It will not be long heating distance needed and the process is space saving. This process can also be done with an unvulcanized rubber.

at The use of a laser also gives you the opportunity to completely cover the granules to melt the middle of the double stripes. This creates a Strip in the middle of the rubber, similar to a foil. The risk of a bad wiping image due to large granule parts is reduced. Instead of a laser can also be a gas burner to be used. However, the temperature stability is not so constant.

alternative can for the warming while the post vulcanization step conventional methods such as oven, Salt bath and the like. Be used.

An alternative method of eliminating oversized granule particles is to mechanically press the granules onto the surface of the squeegee rubber profile after vulcanization. This can be done for example with the help of heated pinch rollers. These are preferably provided above and below the squeegee profile and smooth the granule coating. The smoothing of the granule coating can be limited to the middle region of the wiper rubber profile. Particular preference is given to the use of heatable pressure rollers, since in this way the granules can be smoothed in the molten state. To avoid sticking of the granules to the pressure rollers, their temperature is preferably kept below the melting temperature of the granules used. Furthermore, a plurality of pressure roller pairs are preferably used, wherein the first pair of rollers in the running direction of the rubber profile preferably has a higher temperature than the subsequent roller pairs. In particular, three pairs of rollers are used. Instead of pressure rollers and rollers or similar mechanical pressing devices or a laser device may be provided.

With Help the wiper blade according to the invention let yourself Achieve a very high friction reduction (μ <0.6). In addition, the wear resistance, that is, maintaining excellent wiping quality over the Life of the wiper blade, significantly increased. Other advantages are in the improvement of product quality (noise, abrasion, life, wiping quality, chemical Resistance, no sticking of the wiper on the disk), the possibility the concatenation of extrusion, surface and cutting technology and Online auditability. Furthermore fall in the inventive method no free chlorine, bromine or solvent that's a nuisance of the working environment or corrosion. Furthermore arises less contamination due to detachment of the surface layers and the direct and indirect costs of surface treatment are reduced. In addition, the use of low-performance Electric motors possible and the invention allows greater flexibility in the optical design of the wiper blades.

One Another advantage of the invention is that the wiper blade according to the invention both on hydrophilic windshields (clear glass) and on can be used with those with a water-repellent agent were treated (hydrophobic discs).

Claims (26)

Wiper blade ( 1 ) for a windscreen wiper, in particular a windscreen wiper of a motor vehicle, having a squeegee obtained by vulcanization of a rubber material ( 2 ), which has a squeegee lip ( 3 ), characterized in that on the surface of the wiper blade ( 3 ) a film ( 4 . 7 ) is glued. Wiper blade according to claim 1, characterized in that the film ( 4 . 7 ) is selected from the group consisting of Ultra High Molecular Weight Polyethylene (UHMW-PE), High Molecular Polyethylene (HMW-PE), polyethylene (PE), fluorinated ethylene-propylene (FEP), polyphenylene ether (PPE), perfluoroalkoxy Polymers (PFA), polycarbonate (PC), polyoxymethylene (POM), polyacrylate (PA), polyurethane (PUR), polytetrafluoroethylene (PTFE) and laminates of various thin layers of these materials. Wiper blade according to claim 1 or 2, characterized in that the film ( 4 ) by means of an adhesive ( 6 ) can be applied to the squeegee lip. Wiper blade according to claim 3, characterized in that the adhesive ( 6 ) on the slide ( 7 ) is prefabricated. Wiper blade according to one of claims 1 to 3, characterized in that the film ( 4 . 7 ) only in the front part of the two flanks of the wiper blade ( 3 ) is applied. Wiper blade according to one of claims 1 to 3, characterized in that the film ( 4 . 7 ) in the entire region of the wiper blade ( 3 ) is applied. Wiper blade according to one of the preceding claims, characterized in that the squeegee ( 2 ) is made of a material selected from the group consisting of ethylene-propylene-diene monomer (EPDM), ethylene-propylene monomer (EPM) and chloroprene / natural rubber (CR / NR). Wiper blade ( 1 ) for a windscreen wiper, in particular a windscreen wiper of a motor vehicle, having a squeegee obtained by vulcanization of a rubber material ( 2 ), which has a squeegee lip ( 3 ), characterized in that on the surface of the vulcanized wiper blade ( 3 ) A granule layer is applied. Wiper blade according to claim 8, characterized that the granules are selected is from the group consisting of Ultra High Molecular Weight Polyethylene (UHMW-PE), High Molecular Polyethylene (HMW-PE), Polyethylene (PE), Fluorinated ethylene-propylene (FEP), polyphenylene ether (PPE), perfluoroalkoxy polymers (PFA), polycarbonate (PC), polyoxymethylene (POM), polyacrylate (PA), Polyurethane (PUR), polytetrafluoroethylene (PTFE) and laminates different thin ones Layers of these materials. Wiper blade according to claim 8 or 9, characterized that the grain size of the granules less than 100 μm is. Wiper blade according to one of claims 8 to 10, characterized in that the granular layer only in the front part of the two flanks of the wiper blade ( 3 ) is applied. Wiper blade according to one of claims 8 to 10, characterized in that the granular layer in the entire region of the wiper blade ( 3 ) is applied. Method for producing a wiper blade ( 1 ) for a windshield wiper, in particular a windscreen wiper of a motor vehicle according to one of claims 1 to 7, with a squeegee ( 2 ), which has a squeegee lip ( 3 ), wherein the squeegee ( 2 ) is formed by vulcanization of a shaped synthetic rubber, characterized in that after vulcanization a film ( 4 . 7 ) on the wiper blade ( 3 ) is applied. Method according to claim 13, characterized in that the film ( 4 ) by means of an adhesive ( 6 ) on the wiper blade ( 3 ) is applied. Method according to claim 13, characterized in that the film ( 7 ) is applied as a self-adhesive film. Method for producing a wiper blade ( 1 ) for a windshield wiper, in particular a windscreen wiper of a motor vehicle according to one of claims 8 to 12, with a squeegee ( 2 ), which has a squeegee lip ( 3 ), wherein the squeegee ( 2 ) is formed by vulcanization of a molded synthetic rubber, characterized in that after the vulcanization a granular layer on the wiper blade ( 3 ) is applied. Method according to claim 16, characterized in that that an additional Post vulcanization step is applied, through which the granules chemically is bound to the rubber. Method according to claim 17 , characterized in that the Postvulkanisationsschritt by means of a laser, a gas burner, a salt bath or by IR heating is performed. Method according to one of Claims 16 to 18, characterized that the granule layer applied to a semi-vulcanized rubber becomes. Method according to one of Claims 16 to 18, characterized that the granule layer applied to an unvulcanized rubber is and the vulcanization in the air by acting more energetic Radiation or hot air he follows. Method according to one of Claims 16 to 20, characterized that the granules first in excess is applied to the rubber and then the excess material is removed. Method according to one of Claims 16 to 21, characterized that a primer is used. Wiper blade according to one of claims 16 to 22, characterized in that the granular layer is only in the front part of the two flanks of the wiper blade ( 3 ) is applied. Wiper blade according to one of claims 16 to 22, characterized in that the granulate layer in the entire region of the wiper blade ( 3 ) is applied. Door- or window gasket, in particular for doors or windows of a motor vehicle, with a rubber obtained by vulcanization of a rubber material, having a rubber lip, characterized in that on the surface the rubber lip is glued to a foil. Door- or window gasket, in particular for doors or windows of a motor vehicle, with a rubber obtained by vulcanization of a rubber material, having a rubber lip, characterized in that on the surface the vulcanized rubber lip a granule layer is applied.